Light guide element and lighting fixture

ABSTRACT

A light guide element and a lighting fixture are described. The light guide element includes a light guide body, first microstructures and second microstructures. The light guide body includes a first light-emitting surface and a second light-emitting surface opposite to and parallel to each other. The first microstructures are disposed on the first light-emitting surface in rows. The second microstructures are respectively corresponding to the first microstructures and are disposed on the second light-emitting surface. In each of the rows, each of the first microstructures laps over the corresponding second microstructure in part in a normal direction of the first light-emitting surface. Overlapping ratio of the first microstructures and the corresponding second microstructures become greater from one end of one of the rows to the other end of the one of the rows.

RELATED APPLICATIONS

This application is a continuation-in-part application of U.S.application Ser. No. 13/772,355 filed on Feb. 21, 2013, which claimspriority to Taiwan Application Serial Number 101135985, filed Sep. 28,2012. This application also claims priority to Taiwan Application SerialNumber 101135985, filed Sep. 28, 2012. The entire disclosures of all theabove applications are hereby incorporated by reference herein.

BACKGROUND

1. Field of Invention

The present invention relates to a light guide element, and moreparticularly to a light guide element and a method for manufacturing thesame, and a lighting fixture.

2. Description of Related Art

Currently, in the manufacture of flat panel displays and lightingfixtures, light guide elements are widely used to broaden light-emittingscopes and provide uniform flat emitting light. Accordingly, the lightguide elements have been one of the key components in the flat paneldisplays and the lighting fixtures.

The optical conduction principle of the light guide element is based onthe Snell's Law. When light is going to enter a less dense medium froman optical dense medium, i.e. the light is going to enter the medium ofa lower refractive index from the medium of a high refractive index, andan incident angle is greater than a critical angle, the light is totallyreflected on an interface between the two mediums and cannot enter theless dense medium to advance forward within the optical dense medium. Ascompared with the air, the material of the light guide element is anoptical dense medium,so that if the total reflection of the light on onesurface of the two surfaces of the light guide element, where the lightis totally reflected, is appropriately destroyed, the light can beuniformly emitted from the other surface to form a uniformlight-emitting surface.

However, as the developing of the lighting fixtures, in addition tolighting, the lighting fixtures are sometimes designed forornamentation. Currently, in order to provide a lighting fixtureincluding both functions of lighting and ornamentation, a designedpattern is typically formed on one surface of the light guide element byarranging dots or microstructures according to the designed pattern, soas to make the emitting light of the light guide element show thepattern. However, for obtaining the light-emitting pattern on the localregion of the light-emitting surface, the light is locally concentrated,and the brightness of the whole light-emitting surface is affected, sothat the brightness of the light guide element is decreased, therebyreducing the lighting function of the lighting fixture.

Furthermore, when the pattern composed of the dots or themicrostructures is formed on one surface of the light guide element,defects may be formed on the surface due to the processing. The patterncomposed of the dots or the microstructures is processed based on thedesigned pattern, so that if the pattern has a deviation from theoriginal designed pattern due to the defects, the deviation of thelight-emitting pattern of the light guide element is obvious, therebyreducing the process yield.

SUMMARY

Therefore, one aspect f the present invention is to provide a lightguide element and a method for manufacturing the same, and a lightingfixture, in which two opposite light-emitting surfaces of the lightguide element are respectively set with many first microstructures andmany corresponding second microstructures, and the first microstructureand the second microstructure vertically lap with each other to makeemitting light of each light-emitting surface has a mesh pattern.Therefore, the brightness and the pattern design of the emitting lightof the lighting fixture are both provided.

Another aspect of the present invention is to provide a light guideelement and a method for manufacturing the same, and a lighting fixture,in which mesh patterns of two light-emitting surfaces are effects causedby lapping microstructures of the light-emitting surfaces, so thatpattern defects of the emitting light caused by processing defects isblurred.

According to the aforementioned aspects, the present invention providesa light guide element. The light guide element includes a light guidebody, first microstructures and second microstructures. The light guidebody includes a first light-emitting surface and a second light-emittingsurface opposite to and parallel to each other. The firstmicrostructures are disposed on the first light-emitting surface inrows. The second microstructures are respectively corresponding to thefirst microstructures, and are disposed on the second light-emittingsurface. In each of the rows, each of the first microstructures lapsover the corresponding second microstructure in part in a normaldirection of the first light-emitting surface. Overlapping ratios of thefirst microstructures and the corresponding second microstructuresbecome greater from one end of one of the rows to the other end of theone of the rows.

According to a preferred embodiment of the present invention, the firstmicrostructures include first arrangements and second arrangements. Inthe first arrangements, pattern centers of first ones of the firstmicrostructures are uniformly disposed on first suppositional lines, andthere is an interval between the adjacent first ones on each of thefirst suppositional lines. In the second arrangements, pattern centersof second ones of the first microstructures are uniformly disposed onsecond suppositional lines, there is the interval between the adjacentsecond ones on each of the second suppositional lines, a starting pointof each of the second arrangement is deviated from a starting point ofeach of the first arrangements by a distance, the distance is less thanthe interval, and the first arrangements and the second arrangements areinterlaced.

According to another preferred embodiment of the present invention, thefirst microstructures include a first arrangement and secondarrangements arranged sequentially. In the first arrangement, patterncenters of first ones of the first microstructures are uniformlydisposed on a first suppositional line, and there is an interval betweenthe adjacent first ones. In the second arrangements, pattern centers ofsecond ones of the first microstructures are uniformly disposed onsecond suppositional lines, there is the interval between the adjacentsecond ones on each of the second suppositional lines, and a relationbetween deviation distances of starting points of the secondarrangements from a starting point of the first arrangement anddistances between the second arrangements and the first arrangement is afunctional relation.

According to still another preferred embodiment of the presentinvention, the functional relation is a sinusoidal function relation.

According to further another preferred embodiment of the presentinvention, the first microstructures include a first arrangement andsecond arrangements arranged sequentially. In the first arrangement,pattern centers of first ones of the first microstructures are uniformlyand sequentially arranged in a manner of making heights of the patterncenters of the first ones being apart from a first suppositional linevery as a sinusoidal function, and there is an interval between theadjacent first ones. In each of the second arrangements, pattern centersof second ones of the first microstructures are uniformly andsequentially arranged in a manner of making heights of the patterncenters of the second ones being apart from a second suppositional linevery as a sinusoidal function, there is the interval between theadjacent second ones on each of the second suppositional lines, and arelation between deviation distances of starting points of the secondarrangements from a starting point of the first arrangement anddistances between the second arrangements and the first arrangement is afunctional relation.

According to yet another preferred embodiment of the present invention,the functional relation is a sinusoidal function relation.

According to the aforementioned aspects, the present invention furtherprovides a lighting fixture. The lighting fixture includes theaforementioned light guide element and at least one light source. The atleast one light source is disposed at at least one side of the lightguide element to provide the light guide element with an incident light.

According to the aforementioned aspects, the present invention furtherprovides a light guide element. The light guide element includes a lightguide body, first microstructures and second microstructures. The lightguide body includes a first light-emitting surface and a secondlight-emitting surface opposite to and parallel to each other. The firstmicrostructures are disposed on the first light-emitting surface. Thesecond microstructures are respectively corresponding to the firstmicrostructures, and are disposed on the second light-emitting surface.Each of the first microstructures laps over the corresponding secondmicrostructure in part in a normal direction of the first light-emittingsurface. The first microstructures and the second microstructures havethe same size but different pitches.

According to a preferred embodiment of the present invention, a patterncenter of at least one of the first microstructures is misalignment witha pattern center of t he corresponding second microstructure.

According to another preferred embodiment of the present invention, apattern center of at least one of the first microstructures is alignmentwith a pattern center of the corresponding second microstructure.

According to the aforementioned aspects, the present invention furtherprovides a lighting fixture. The lighting fixture includes theaforementioned light guide element and at least one light source. The atleast one light source is disposed at at least one side of the lightguide element to provide the light guide element with an incident light.

According to the aforementioned aspects, the present invention furtherprovides a light guide element. The light guide element includes a lightguide body, first microstructures and second microstructures. The lightguide body includes a first light-emitting surface and a secondlight-emitting surface opposite to and parallel to each other. The firstmicrostructures are disposed on the first light-emitting surface. Thesecond microstructures are respectively corresponding to the firstmicrostructures, and are disposed on the second light-emitting surface.Each of the first microstructures laps over the corresponding secondmicrostructure in part in a normal direction of the first light-emittingsurface. The first microstructures and the second microstructures havethe same pitch but different sizes.

According to a preferred embodiment of the present invention, a patterncenter of at least one of the first microstructures is misalignment witha pattern center of the corresponding second microstructure.

According to another preferred embodiment of the present invention, apattern center of at least one of the first microstructures is alignmentith a pattern center of the corresponding second microstructure.

According to the aforementioned aspects, the present invention furtherprovides a lighting fixture. The lighting fixture includes theaforementioned light guide element and at least one light source. The atleast one light source is disposed at at least one side of the lightguide element to provide the light guide element with an incident light.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing aspects and many of the attendant advantages of thisinvention are more readily appreciated as the same become betterunderstood by reference to the following detailed description, whentaken in conjunction with the accompanying drawings, wherein:

FIG. 1 is a schematic diagram showing a lighting fixture in accordancewith an embodiment of the present invention;

FIG. 2 is a schematic diagram showing an arrangement rule ofmicrostructures in accordance with an embodiment of the presentinvention;

FIG. 3 is a schematic diagram showing an arrangement rule ofmicrostructures in accordance with another embodiment of the presentinvention;

FIG. 4 is a schematic diagram showing an arrangement rule ofmicrostructures in accordance with still another embodiment of thepresent invention;

FIG. 5 illustrates a top view of the lapping of first microstructuresand second microstructures of a light guide element in accordance withanother embodiment of the present invention;

FIG. 6 illustrates a top view of the lapping of first microstructuresand second microstructures of a portion of a light guide element inaccordance with an embodiment of the present invention;

FIG. 7 illustrates a top view of the lapping of first microstructuresand second microstructures of a portion of a light guide element inaccordance with an embodiment of the present invention;

FIG. 8 illustrates a top view of the lapping of first microstructuresand second microstructures of a portion of a light guide element inaccordance with an embodiment of the present invention; and

FIG. 9 illustrates a top view of the lapping of first microstructuresand second microstructures of a portion of a light guide element inaccordance with an embodiment of the present invention.

DETAILED DESCRIPTION

Refer to FIG. 1. FIG. 1 is a schematic diagram showing a lightingfixture in accordance with an embodiment of the present invention. Inthe present embodiment; a lighting fixture 100 mainly includes a lightguide element 110 and one or more light source, such as a light source116. The light source 116 is disposed at one side of the light guideelement 110 to provide the light guide element 110 with an incidentlight from the side of the light guide element 110.

The light guide element 110 includes a light guide body 102, a pluralityof first microstructures 118 and a plurality of second microstructures120. The light guide body 102 includes a first light-emitting surface104 and a second light-emitting surface 106. The firstlight-emittingsurface 104 and the second light-emitting surface 106 are opposite toeach other, and parallel to each other. In addition, the light guidebody 102 further includes a light-incidence surface 108, in which thelight-incidence surface 108 is adjacent to the light source 116 and twoopposite sides of the light-incidence surface 108 are respectivelyconnected to the first light-emitting surface 104 and the secondlight-emitting surface 106. Light emitted from the light source 116 canenters the light guide element 110 through the light-incidence surface108. The light-incidence surface 108 of the light guide element 110 isdecided in relation to the light source 116, so that a side surface ofthe light guide element 110 that the light emitted from the light source116 passes through to enter the light guide element 110 is referred as alight-incidence surface 108.

The light source 116 may be a light-emitting diode (LED) light bar or alamp tube. In one exemplary embodiment, such as shown in FIG. 1, thelight source 116 is a LED light bar and includes a circuit board 114 anda plurality of light-emitting diodes 112. The light-emitting diodes 112are disposed on the circuit board 114 and are all electrically connectedto a circuit of the circuit board 114. The light-emitting diodes 112emit light toward the light incidence surface 108 of the light guideelement 110.

The light guide element 110 mainly includes the light guide body 102,the first microstructures 118 and the second microstructures 120, sothat in the fabrication of the light guide element 110, the light guidebody 102 is firstly provided, and the first microstructures 118 and thesecond microstructures 120 are respectively disposed on the firstlight-emitting surface 104 and the second light-emitting surface 106.

In the light guide element 110, the first microstructures 118 aredisposed and distributed on the entire first light-emitting surface 104of the light guide body 102. On the other side, the secondmicrostructures 120 are disposed and distributed on the entire secondlight-emitting surface 106 of the light guide body 102. In someexamples, the first microstructures 118 are disposed on the firstlight-emitting surface 104 in rows. In certain examples, the firstmicrostructures 118 and the second microstructures 120 may berespectively arranged based on a first datum line and a second datumline, which are different from each other, and by a first arrangementrule and a second arrangement rule. In one exemplary embodiment, thesecond datum line is rotationally deviated in relation to the firstdatum line with an angle to form an included angle between the seconddatum line and the first datum line. In addition, the first arrangementrule of the first microstructures 118 and the second arrangement rule ofthe second microstructures 120 may be identical. The firstmicrostructures 118 respectively correspond to the secondmicrostructures 120. Furthermore, in a normal direction 126 of the firstlight-emitting surface 104, i.e. in a vertical direction, each firstmicrostructure 118 laps over the corresponding second microstructure 120in part.

In one exemplary embodiment, the first microstructures 118 and thesecond microstructures 120 have the same size and the same shape. Inanother exemplary embodiment, the first microstructures 118 and thesecond microstructures 120 may have different sizes and differentshapes, or may have the same shape and different sizes. The shape of thefirst microstructures and the second microstructures 120 may be acircular form, an elliptical form, a triangular form, a square form, apolygonal form or an irregular form, such as a stellar form and a heartform.

Refer to FIG. 2. FIG. 2 is a schematic diagram showing an arrangementrule of microstructures in accordance with an embodiment of the presentinvention. In the present embodiment, the first microstructures 118 aretaken to illustrate their first arrangement rule. In the condition,which the first arrangement rule of the first microstructures 118 andthe second arrangement rule of the second microstructures 120 areidentical, the illustration made according to FIG. 2 can also be as theillustration for the second arrangement rule of the secondmicrostructures 120.

In the present embodiment, the first datum line may be defined firstly.The first datum line may be any side of the first light-emitting surface104, for example. First microstructures 118 a (i.e. first ones of thefirst microstructures 118) and 118 b (i.e. second ones of the firstmicrostructures 118) may be respectively divided into a plurality offirst arrangements 122 and a plurality of second arrangements 124. Eachof the first arrangements 122 and the second arrangements 124 is one rowof the first microstructures 118 a and 118 b. The first arrangements 122and the second arrangements 124 are interlaced on the firstlight-emitting surface 104 to distribute on the entire desired region,such as the entire first light-emitting surface 104 or a partial regionof the first light-emitting surface 104. In addition, the adjacent firstarrangement 122 and the second arrangement 124 are separated from eachother with an interval d₂.

In each first arrangement 122, several first microstructures 118 a aredisposed on a first suppositional line L₁, which may be parallel to thefirst datum line, to uniformly arrange pattern centers of the firstmicrostructures 118 a on the first suppositional line L₁, i.e. the firstmicrostructures 118 a are disposed equidistantly. Therefore, on eachfirst suppositional line L₁, any adjacent two of first microstructures118 a have a same interval d₁.

In each second arrangement 124, several first microstructures 118 b aredisposed on a second suppositional line L₂, which may be parallel to thefirst datum line, to uniformly arrange pattern centers of the firstmicrostructures 118 b on the second suppositional line L₂, i.e. thefirst microstructures 118 b are disposed equidistantly. In addition, oneach second suppositional line L₂, any adjacent two of firstmicrostructures 118 b also have the same interval d₁. In each secondarrangement 124, a starting point for disposing the firstmicrostructures 118 b is deviated from a starting point for disposingthe first microstructures 118 a of each first arrangement 122 by adistance S₁. Furthermore, the distance S₁ is less than the interval d₁between two adjacent first microstructures 118 a or 118 b.

Refer to FIG. 3. FIG. 3 is a schematic diagram showing an arrangementrule of microstructures in accordance with another embodiment of thepresent invention. In the present embodiment, the first microstructures118 are taken to illustrate their first arrangement rule similarly. Inthe condition, which the first arrangement rule of the firstmicrostructures 118 and the second arrangement rule of the secondmicrostructures 120 are identical, the illustration made according toFIG. 3 can also be as the illustration for the second ngement rule ofthe second microstructures 120 similarly.

In the present embodiment, the first datum line may be defined firstly.The first datum line may be any side of the first light-emitting surface104, for example. First microstructures 118 a (i.e. first ones of thefirst microstructures 118) and 118 b, 118 c, 118 d and 118 e (i.e.second ones of the first microstructures 118) may be respectivelydivided into one first arrangement 122 and a plurality of secondarrangements 124 a, 124 b, 124 c and 124 d. The first arrangement 122and the second arrangements 124 a, 124 b, 124 c and 124 d are disposedon the first light-emitting surface 104 in sequence to form a periodicalarrangement. The first arrangement 122 and the second arrangements 124a, 124 b, 124 c and 124 d are arranged in sequence to distribute on theentire desired region, such as the entire first light-emitting surface104 or a partial region of the first light-emitting surface 104, by theperiodical arrangement. In addition, any adjacent two of the firstarrangement 122 and the second arrangements 124 a, 124 b, 124 c and 124d are separated from each other with an interval d₂.

In the first rangement 122, several first microstructures 118 a aredisposed on a first suppositional line L₁, which may be parallel to thefirst datum line, to uniformly arrange pattern centers of the firstmicrostructures 118 a on the first suppositional line L₁, i.e. the firstmicrostructures 118 a are disposed equidistantly. Therefore, on thefirst suppositional line L₁, any adjacent two of first microstructures118 a have a same interval d₁.

In the second arrangements 124 a, 124 b, 124 c and 124 d, several firstmicrostructures 118 b, 118 c, 118 d and 118 e are respectively disposedon second suppositional lines L₂₁, L₂₂, L₂₃ and L₂₄, which may beparallel to the first datum line, to uniformly arrange pattern centersof the first microstructures 118 b, 118 c, 118 d and 118 e on the secondsuppositional line L₂₁, L₂₂, L₂₃ and L₂₄ respectively, i.e. the firstmicrostructures 118 b, 118 c, 118 d and 118 e are respectively disposedequidistantly. In addition, on the second suppositional lines L₂₁, L₂₂,L₂₃ and L₂₄, any adjacent two of first microstructures 118 b, 118 c, 118d and 118 e also have the same interval d₁.

In the second arrangements 124 a, 124 b, 124 c and 124 d, startingpoints for disposing the first microstructures 118 b, 118 c, 118 d and118 e are respectively deviated from a starting point for disposing thefirst microstructures 118 a by one distance S₁, a distance being twiceas far as the distance S₁, one distance S₁ and zero. The distance S₁ isless than the interval d₁ between two adjacent first microstructures 118a, 118 b, 118 c, 118 d and 118 e. In the present embodiment, a relationbetween deviation distances of the starting points of the secondarrangements 124 a, 124 b, 124 c and 124 d from the starting point ofthe first arrangement 122 and distances between the second arrangements124 a, 124 b, 124 c and 124 d and the first arrangement 122 can bedefined as a functional relation. In one exemplary embodiment, thefunction may be a sinusoidal function, such as the following formula(1).

S=S _(max) sin x  (1)

In the formula (1), the value S represents the deviation distance of thestarting point of the microstructures of each arrangement, and the valueS_(max) represents the amplitude of the sinusoidal function and alsorepresents the largest deviation distance. In addition, the valuex≡2π[(n−1)d/D], in which the number n is a positive integer andrepresents the nth arrangement, the value (n−1)d represents the intervalbetween each arrangement and the first arrangement 122, and the value Drepresents the overall distance of the whole function period.

For example, the number n of the first arrangement 122 is 1, and now thevalue x≡2π[(n−1)d/D]=2π[(1−1)d₂/D]=0. The number n of the secondarrangement 124 a is 2, now the valuex≡2π[(n−1)d/D]=2π[(2−1)d₂/D]=2π(d₂/D), and the deviation distance of thestarting point of the first microstructures 118 b of the secondarrangement 124 a is S=S_(max) sin[2π(d₂/D)]=the distance S₁. The numbern of the next second arrangement 124 b is 3, now the valuex≡2π[(n−1)d/D]=2π[(2−1)d₂/D]=2π(d₂/D), and the deviation distance of thestarting point of the first microstructures 118 c of the secondarrangement 124 b is S=S_(max) sin[2π(2d₂/D)]=a distance being twice asfar as the distance S₁. The following arrangements are analogized insequence.

Refer to FIG. 4. FIG. 4 is a schematic diagram showing an arrangementrule of microstructures in accordance with still another embodiment ofthe present invention. In the present embodiment, the firstmicrostructures 118 are taken to illustrate their first arrangement rulesimilarly. In the condition, which the first arrangement rule of thefirst microstructures 118 and the second arrangement rule of the secondmicrostructures 120 are identical, the illustration made according toFIG. 4 can also be as the illustration for the second arrangement ruleof the second microstructures 120 similarly.

In the present embodiment, the first datum line may be defined firstly.The first datum line may be any side of the first light-emitting surface104, for example. First microstructures 118 a ₁, 118 a ₂, 118 a ₃ and118 a ₄ (i.e. first ones of the first microstructures 118), and 118 b ₁,118 b ₂, 118 b ₃, 118 b ₄, 118 c ₁, 118 c ₂, 118 c ₃ and 118 c ₄ (i.e.second ones of the first microstructures 118) may be respectivelydivided into one first arrangement 122 a and a plurality of secondarrangements 124 e and 124 f. The first arrangement 122 a, a secondarrangement 124 e and a second arrangement 124 f are disposed on thefirst light-emitting surface 104 in sequence, and the subsequentarrangements proceed according to an arrangement rule of arranging thesecond arrangements 124 e and 124 f sequentially to distribute on theentire desired region, such as the entire first light-emitting surface104 or a partial region of the first light-emitting surface 104. Inaddition, any adjacent two of the first arrangement 122 a and the secondarrangements 124 e and 124 f are separated from each other with aninterval d₂.

In the first arrangement 122 a, several first microstructures 118 a ₁,118 a ₂, 118 a ₃ and 118 a ₄ are uniformly and periodically disposed ona first suppositional line L₁, may be parallel to the first datum line,in a manner of arranging pattern centers of the first microstructures118 a ₁, 118 a ₂, 118 a ₃ and 118 a ₄ sequentially on the firstsuppositional line L₁, being higher than the first suppositional line L₁with a first height, on the first suppositional line L₁, being lowerthan the first suppositional line L₁ with a second height. As shown inFIG. 4, the first height and the second height may be identical, each ofwhich is a height S₂, for example. On the first suppositional lines L₁,any adjacent two of first microstructures 118 a ₁, 118 a ₂, 118 a ₃ and118 a ₄ have the same interval d₁.

In the second arrangements 124 e and 124 f, several firstmicrostructures 118 b ₁, 118 b ₂, 118 b ₃ and 118 b ₄ and several firstmicrostructures 118 c ₁, 118 c ₂, 118 c ₃ and 118 c ₄ are respectivelydisposed on second suppositional lines L₂₁ and L₂₂, which may beparallel to the first datum line, in a manner of arranging patterncenters of the first microstructures 118 b ₁, 118 b ₂, 118 b ₃ and 118 b₄ sequentially on the second suppositional line L₂₁, being higher thanthe second suppositional line L₂₁ with a first height, on the secondsuppositional line L₂₁, and being lower than the second suppositionalline L₂₁ with a second height, and arranging pattern centers of thefirst microstructures 118 c ₁, 118 c ₂, 118 c ₃ and 118 c ₄ sequentiallyon the second suppositional line L₂₂, being higher than the secondsuppositional line L₂₂ with one height S₂, on the second suppositionalline L₂₂, and being lower than the second suppositional line L₂₂ withone height S₂. In addition, on the second suppositional lines L₂₁ andL₂₂, any adjacent two of first microstructures 118 b ₁, 118 b ₂, 118 b ₃and 118 b ₄, and any adjacent two of first microstructures 118 c ₁, 118c ₂, 118 c ₃ and 118 c ₄ also have the same interval d₁.

In the second arrangements 124 e and 124 f, starting points fordisposing the first microstructures 118 b ₁ and 118 c ₁ are respectivelydeviated from a starting point for disposing the first microstructures118 a ₁ of the first arrangement 122 a by one distance S₁ and a distancebeing twice as far as the distance S₁. Next, starting points of aplurality of second arrangements sequentially arranged under the secondarrangement 124 f are respectively apart from the starting point of thefirst arrangement 122 a by deviation distances, which are increasingprogressively by one distance S₁ in sequence. The distance S₁ is lessthan the interval d₁ between two adjacent first microstructures 118 b ₁,118 b ₂, 118 b ₃ and 118 b ₄ or between two adjacent firstmicrostructures 118 c ₁, 118 c ₂, 118 c ₃ and 118 c ₄.

In the present embodiments the arrangements of the microstructures oneach suppositional line can be defined as a functional relation. In oneexemplary embodiment, the function may be a sinusoidal function, such asthe following formula (2).

H=H _(max) sin x  (2)

In the formula (2), the value H represents the deviation height of thestarting point of the microstructures of each arrangement, and the valueH_(max) represents the amplitude of the sinusoidal. function and alsorepresents the largest deviation height. In addition, the valuex≡2π[(n−1)d/L], in which the number n is a positive integer andrepresents the nth microstructure in one arrangement, the value (n−1)drepresents the distance between one first microstructure in onearrangement and the starting point of the arrangement, and the value Lrepresents the overall distance of the whole function period.

For example, in the first arrangement 122 a, the number n of the firstmicrostructure 118 a ₁ from the start is 1, and now the valuex≡2π[(n−1)d/L]=2π[(1−1)d₁/L]=0. The number n of the next firstmicrostructure 118 a ₂ is 2, now the valuex≡2π[(n−1)d/L]=2π[(2−1)d₁/L]=2π(d₁/L), and the deviation height of thefirst microstructure 118 a ₂ is H=H_(max) sin[2π(d₁/L)]=the height S₂.The number n of the next first microstructure 118 a ₃ is 3, now thevalue x=2π[(3−1)d₁/L]=2π(2d₁/L), and the deviation height of the firstmicrostructure 118 a ₃ is H=H_(max) sin[2π(2d₁/L)]=0 because L=4d₁ inthe example. The following arrangements are analogized in sequence. Inthe present embodiment, a relation between deviation distances of thestarting points of the second rangements 124 e and 124 f from thestarting point of the first arrangement 122 a and distances between thesecond arrangements 124 e and 124 f and the first arrangement 122 a canbe defined as a functional relation. In one exemplary embodiment, thefunction may be a sinusoidal function, such as the aforementionedformula (1). Referring to FIG. 1 again, after disposing the firstmicrostructures 118 on the first light-emitting surface 104 and thesecond microstructures 120 on the second light-emitting surface 106 ofthe light guide element 110, the second datum line is rotationallydeviated in relation to the first datum line, so that each firstmicrostructure 118 laps over the corresponding second microstructure 120in part in the normal direction 126 of the first light-emitting surface104.

For example, referring to FIG. 1 and FIG. 5, in which FIG. 5 illustratesa top view of the lapping of first microstructures and secondmicrostructures of a light guide element in accordance with anotherembodiment of the present invention. In the present embodiment, whenviewing the light guide element 110 in a direction from the top of thefirst light-emitting surface 104 toward the second light-emittingsurface 106, the second datum line is rotationally deviated in relationto the first datum line with an angle, so that an included angle, suchas an included angle α, is formed between each of the firstsuppositional line L₁ and the second suppositional lines L₂₁, L₂₂, L₂₃and L₂₄ on the first light-emitting surface 104 and the correspondingfirst suppositional line R₁ and the second suppositional lines R₂₁, R₂₂,R₂₃ and R₂₄ on the second light-emitting surface 106.

Therefore, each of the first microstructures 118 a, 118 b, 118 c, 118 dand 118 e on the first light-emitting surface 104 and the correspondingsecond microstructures 120 a, 120 b, 120 c, 120 d and 120 e on the,second light-emitting surface 106 are partially staggered and partiallylaps. As shown in FIG. 5, in each row which respectively include thefirst microstructures 118 a, 118 b, 118 c, 118 d or 118 e, overlappingratios of the first microstructures 118 a, 118 b, 118 c, 118 d or 118 eand the corresponding second microstructures 120 a, 120 b, 120 c, 120 dand 120 e become greater from one end 128 of one of the rows to theother end 130 of the one of the rows

According to the Moiré effect, it is known that when two or moreregularly arranged patterns laps with each other with some includedangle, another regularly arranged pattern would be formed. Therefore, byregularly arranging the first microstructures 118 a, 118 b, 118 c, 118 dand 118 e on the first light-emitting surface 104 and the secondmicrostructures 120 a, 120 b, 120 c, 120 d and 120 e on the secondlight-emitting surface 106, when an incident light enters the lightguide body 102 of the light guide element 110, the emitting light canrespectively form a first mesh pattern and a second mesh pattern on thefirst light-emitting surface 104 and the second light-emitting surface106. The first mesh pattern and the second mesh pattern may be formeddue to the Moiré effect, so that they may be also referred as Moiré meshpatterns.

In one exemplary embodiment, after completing the arrangement design ofthe first microstructures 118 and the second microstructures 120, arandom disturbance may be added to the position of each firstmicrostructure 118 and second microstructure 120. However, the randomdisturbance should not be too large, so as to keep the Moiré meshes. Inaddition, after completing the arrangement design of the firstmicrostructures 118 and the second microstructures 120, sizes of thefirst microstructures 118 and the second microstructures 120 can bemodified according to the desired luminous flux of the region, in whichthe sizes of the first microstructures 118 and the secondmicrostructures 120 is directly proportional to the luminous flux.

Referring to FIG. 1 and FIG. 6, in which FIG. 6 illustrates a top viewof the lapping of first microstructures and second microstructures of aportion of a light guide element in accordance with an embodiment of thepresent invention. In the present embodiment, the first microstructures118 disposed on a first suppositional line L₁ and the secondmicrostructures 120 disposed on a first suppositional line R₁ have thesame size but different pitches. In some examples, when viewing thelight guide element 110 in a direction from the top of the firstlight-emitting surface 104 toward the second light-emitting surface 106,a pattern center of at least one of the first microstructures 118 ismisalignment with a pattern center of the corresponding secondmicrostructure 120.

Referring to FIG. 1 and FIG. 7, in which FIG. 7 illustrates a top viewof the lapping of first microstructures and second microstructures of aportion of a light guide element in accordance with an embodiment of thepresent invention. In the present embodiment, the first microstructures118 disposed on a first suppositional line L₁ and the secondmicrostructures 120 disposed on a first suppositional line R₁ have thesame size but different pitches. In some examples, when viewing thelight guide element 110 in a direction from the top of the firstlight-emitting surface 104 toward the second light-emitting surface 106,a pattern center of at least one of the first microstructures 118 (suchas the right one of the first microstructures 118 in FIG. 7) isalignment with a pattern center of the corresponding secondmicrostructure 120 while a pattern center of the other one of the firstmicrostructures 118 (such as the left one of the first microstructures118 in FIG. 7) may be misalignment with a pattern center of thecorresponding second microstructure 120.

Referring to FIG. 1 and FIG. 8, in which FIG. 8 illustrates a top viewof the lapping of first microstructures and second microstructures of aportion of a light guide element in accordance with an embodiment of thepresent invention. In the present embodiment, the first microstructures118 disposed on a first suppositional line L₁ and the secondmicrostructures 120 disposed on a first suppositional line R₁ have thesame pitch but different sizes. For example, as shown in FIG. 8, thesize of the first microstructures 118 is smaller than that of the secondmicrostructures 120. In some examples, when viewing the light guideelement 110 in a direction from the top of the first light-emittingsurface 104 toward the second light-emitting surface 106, a patterncenter of at least one of the first microstructures 118 is misalignmentwith a pattern center of the corresponding second microstructure 120.

Referring to FIG. 1 and FIG. 9, in which FIG. 9 illustrates a top viewof the lapping of first microstructures and second microstructures of aportion of a light guide element in accordance with an embodiment of thepresent invention. In the present embodiment, the first microstructures118 disposed on a first suppositional line L₁ and the secondmicrostructures 120 disposed on a first suppositional line R₁ have thesame pitch but different sizes. For example, as shown in FIG. 9, thesize of the first microstructures 118 is smaller than that of the secondmicrostructures 120. In some examples, each of the first microstructures118 is completely covered by the corresponding second microstructure120, and when viewing the light guide element 110 in a direction fromthe top of the first light-emitting surface 104 toward the secondlight-emitting surface 106, a pattern center of at least one of thefirst microstructures 118 is alignment with a pattern center of thecorresponding second microstructure 120.

When the method of the present invention is used to manufacture a lightguide element, luminous intensities of various regions on light-emittingsurfaces of the light guide element can be decided according to the realdemand of a lighting fixture. Furthermore, when the light guide elementis applied to the lighting fixture, each of the two light-emittingsurfaces is set with a pattern composed of a plurality ofmicrostructures. The microstructures have less influence on thebrightness, so that the brightness and the pattern design of theemitting light of the lighting fixture are both considered. Moreover,mesh patterns of the two light-emitting surfaces of the light guideelement in the present invention are effects caused by lappingmicrostructures of the light-emitting surfaces, so that pattern defectsof the emitting light caused by processing defects is blurred.

In addition, the mesh patterns formed on the light-emitting surfaces ofthe light guide element by the method of the present invention vary asthe change of observation angle of an observer. Therefore, compared withthe constant pattern formed by directly arranging the microstructuresconventionally, the patterns of the emitting light of the light guideelement of the present invention are more animated and more variable.Accordingly, when the light guide element is applied to a decorativelighting fixture, a novel design is obtained.

The Moiré mesh can be eliminated by adjusting the arrangement angle ofthe microstructures of the two light-emitting surfaces in the method ofthe present invention. The arrangement rule of the present invention iseasier, so that it is cheaper as compared with a conventionalelimination method of a Moiré mesh by a random arrangement.

As is understood by a person skilled in the art, the foregoing preferredembodiments of the present invention are illustrative of the presentinvention rather than limiting of the present invention. It is intendedto cover various modifications and similar arrangements included withinthe spirit and scope of the appended claims, the scope of which shouldbe accorded the broadest interpretation so as to encompass all suchmodifications and similar structure.

What is claimed is:
 1. A light guide element, including: a light guidebody including a first light-emitting surface and a secondlight-emitting surface opposite to and parallel to each other; pluralityof first microstructures, wherein the first microstructures are disposedon the first light-emitting surface in rows; and a plurality of secondmicrostructures respectively corresponding to the first microstructures,wherein the second microstructures are disposed on the secondlight-emitting surface; wherein in each of the rows, each of the firstmicrostructures laps over the corresponding second microstructure inpart in a normal direction of the first light-emitting surface, andwherein overlapping ratios of the first microstructures and thecorresponding second microstructures become greater from one end of oneof the rows to the other end of the one of the rows.
 2. The light guideelement according to claim 1, wherein the first microstructures include:a plurality of first arrangements, wherein in the first arrangements, aplurality of pattern centers of a plurality of first ones of the firstmicrostructures are uniformly disposed on a plurality of firstsuppositional lines, and there is an interval between the adjacent firstones on each of the first suppositional lines; and a plurality of secondarrangements, wherein in the second arrangements, a plurality of patterncenters of a plurality of second ones of the first microstructures areuniformly disposed on a plurality of second suppositional lines, thereis the interval between the adjacent second ones on each of the secondsuppositional lines, a starting point of each of the second arrangementis deviated from a starting point of each of the first arrangements by adistance, the distance is less than the interval, and the firstarrangements and the second arrangements are interlaced.
 3. The lightguide element according to claim 1, wherein the first microstructuresinclude: a first arrangement, wherein in the first arrangement, aplurality of pattern centers of a plurality of first ones of the firstmicrostructures are uniformly disposed on a first suppositional line,and there is an interval between the adjacent first ones; and aplurality of second arrangements arranged sequentially, wherein in thesecond arrangements, a plurality of pattern centers of a plurality ofsecond ones of the first microstructures are uniformly disposed on aplurality of second suppositional lines, there is the interval betweenthe adjacent second ones on each of the second suppositional lines, anda relation between deviation distances of starting points of the secondarrangements from a starting point of the first arrangement anddistances between the second arrangements and the first arrangement is afunctional relation.
 4. The light guide element according to claim 3,wherein the functional relation is a sinusoidal function relation. 5.The light guide element according to claim 1, wherein the firstmicrostructures include: a first arrangement, wherein in the firstarrangement, a plurality of pattern centers of a plurality of first onesof the first microstructures are uniformly and sequentially arranged ina manner of making heights of the pattern centers of the first onesbeing apart from a first suppositional line very as a sinusoidalfunction, and there is an interval between the adjacent first ones; anda plurality of second arrangements arranged sequentially, wherein ineach of the second arrangements, a plurality of pattern centers of aplurality of second ones of the first microstructures are uniformly andsequentially arranged in a manner of making heights of the patterncenters of the second ones being apart from a second suppositional linevery as a sinusoidal function, there is the interval between theadjacent second ones on each of the second suppositional lines, and arelation between deviation distances of starting points of the secondarrangements from a starting point of the first arrangement anddistances between the second arrangements and the first arrangement is afunctional relation.
 6. The light guide element according to claim 5,wherein the functional relation is a sinusoidal function relation.
 7. Alighting fixture including the light guide element according to claim 1,and at least one light source disposed at at least one side of the lightguide element to provide the light guide element with an incident light.8. A light guide element, including: a light guide body including afirst light-emitting surface and a second light-emitting surfaceopposite to and parallel to each other; a plurality of firstmicrostructures, wherein the first microstructures are disposed on thefirst light-emitting surface; and a plurality of second microstructuresrespectively corresponding to the first microstructures, wherein thesecond microstructures are disposed on the second light-emittingsurface; wherein each of the first microstructures laps over thecorresponding second microstructure in part in a normal direction of thefirst light-emitting surface; and wherein the first microstructures andthe second microstructures have the same size but different pitches. 9.The light guide element according to claim 8, wherein a pattern centerof at least one of the first microstructures is misalignment with apattern center of the corresponding second microstructure.
 10. The lightguide element according to claim 8, wherein a pattern center of at leastone of the first microstructures is alignment with a pattern center ofthe corresponding second microstructure.
 11. A lighting fixtureincluding the light guide element according to claim 8, and at least onelight source disposed at at least one side of the light guide element toprovide the light guide element with an incident light.
 12. A lightguide element, including: a light guide body including a firstlight-emitting surface and a second light-emitting surface opposite toand parallel to each other; a plurality of first microstructures,wherein the first microstructures are disposed on the firstlight-emitting surface; and a plurality of second microstructuresrespectively corresponding to the first microstructures, wherein thesecond microstructures are disposed on the second light-emittingsurface; wherein each of the first microstructures laps over thecorresponding second microstructure in part in a normal direction of thefirst light-emitting surface; and wherein the first microstructures andthe second microstructures have the same pitch but different sizes. 13.Thelight guide element according to claim 12, wherein a pattern centerof at least one of the first microstructures ismisalignment with apattern center of the corresponding second microstructure.
 14. The lightguide element according to claim 12, wherein a pattern center of atleast one of the first microstructures is alignment with a patterncenter of the corresponding second microstructure.
 15. A lightingfixture including the light guide element according to claim 12, and atleast one light source disposed at at least one side of the light guideelement to provide the light guide element with an incident light.